Taking back the night sky

Can we dim the lights in some parts of Australia to bring back the wonders of the night sky?

Professor Fred Watson, AM, is astronomer-in-charge of the Australian Astronomical Observatory in Coonabarabran, NSW, and regular columnist.

IT TAKES ABOUT 20 minutes – longer if you’ve just left the glare of fluorescent lights, but rather less if it was only the glow of a desk lamp. Either way, the result is the same.

Your exposure to complete darkness triggers a sequence of biochemical processes in your eyes, rendering them a million times more sensitive than they were in daylight. You have become dark-adapted.

Your abilities in this condition might surprise you. If the sky is clear, the light from the stars alone is sufficient to illuminate your path. There’s no need for moonlight. And, on the ground, you might even be able to see your shadow, silhouetted by the gossamer band of the Milky Way. But this remarkable response to darkness is denied to most of us by our high-intensity nightscape.

Light pollution problem

Even when we sleep, we’re seldom in a completely light-free environment. So why should we cherish a primitive faculty that has been made largely redundant by the dazzling lifestyle of the 21st century?

The answer is that our wellbeing depends on it. The loss of darkness inhibits the secretion of melatonin, the sleep-inducing hormone, and shift workers are well aware of the detrimental effects of trying to sleep at the wrong time and in the wrong environment.

But there’s a more subtle consequence of our enforced detachment from darkness. Before the growth of big cities, the stars were the evening’s entertainment.

That connection brought with it a solid foundation for life’s trials and tribulations, a tangible assurance that in the heavens, at least, all was well. For most of us – irrespective of our cultural background – that bastion has gone.

Outback star spectacular

Can we regain this lost Eden? I believe we can – particularly here in Australia. Our nation is better off than most. Although the continent is ringed with cities, it boasts stunning expanses of emptiness. Often those havens of darkness are within reach.

Moreover, there’s a growing awareness that light can harm the environment, particularly nocturnal and migrating species. And that wasted light has a greenhouse footprint.

The reason cities are so bright is that they evolved largely without rules. Until a few decades ago, if you wanted to install a row of street lamps, you paid little heed to where the light went. The fact that some radiated uselessly into the sky was of no consequence if the street was adequately illuminated. The same was true of sportsgrounds, industrial complexes and coalmines.

So the glow of light pollution grew inexorably with development. And, thanks to the light-transmitting properties of the atmosphere, its insidious fingers extended tens of kilometres beyond city boundaries.

Although that legacy remains, designs and regulations have improved. Newer fittings direct the light exactly where it’s needed, with not a skerrick leaking upwards. I am hopeful that this will begin to reduce the damaging spill of light, particularly with the advent of light-emitting diodes (LEDs).

A recent meeting of lighting designers at Sydney Observatory sent a clear message – to make a city beautiful, and safe, you don’t need to light absolutely everything.

International Dark Sky Association

Not surprisingly, it is observatories that have led the crusade against light pollution. The peak advocacy body for good outdoor lighting – the International Dark Sky Association(IDA) – had its origins in the 1980s, when astronomers at major US observatories became alarmed by night-sky degradation.

Large telescopes are major investments and need complete freedom from light pollution. That advocacy is alive and well in Australia, too, where Sydney lighting consultant Reginald Wilson represents the IDA.

But the best bit is that the IDA is not just for astronomers – it’s for everyone. And so, the association has launched its International Dark Sky Places program, which recognises the planet’s accessible, pristine skies. A handful have qualified worldwide. The IDA also acknowleges communities with “exceptional dedication to the preservation of the night sky”.

Our national observatory is located at Siding Spring, near Coonabarabran, NSW. Close to the beautiful Warrumbungle National Park, it is already a dark site, protected by state legislation, and an obvious candidate for our first IDA-recognised place.

With support from Australian Geographic, the observatory is working towards that recognition.